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My 2002 WJ Laredo (4.7 V8, 4 WD, towing and up-country suspension packages) is coming up on 100,000 miles. That’s not a typo - that’s 100K.

I’ve been getting the oil changed about every 3,000 miles and whatever fixed when it’s needed. But I’m curious if there’s anything extra I should do when it hits 100,000.

It’s not my primary driver. It’s mostly used for long and longer distances. It does get some around town use but recently I’ve been driving about 70 miles round trip (35 each way mostly freeway driving one way and clear freeway driving the way back) 4-5 days a week for the last couple of months. That will probably continue for the next several weeks. Before that, it wasn’t getting that much driving. Some around town and the occasional freeway trip of about 60 miles to get everything up to operating temperature.

I’ve used it over the years to trailer vehicles and sadly it’s only been off-road a few times and even then that was limited.
 

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I just picked up an 02 4.7 with 99k on it, waiting to see the replies. I’ll be going through and changing all fluids, trans service, hoses, belts, etc. I always figure if the consumables lasted for the first 100k, a refresh will keep it going another 100k. YMMV
 

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2004 WJ Overland
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My 2002 WJ Laredo (4.7 V8, 4 WD, towing and up-country suspension packages) is coming up on 100,000 miles. That’s not a typo - that’s 100K.

I’ve been getting the oil changed about every 3,000 miles and whatever fixed when it’s needed. But I’m curious if there’s anything extra I should do when it hits 100,000.

It’s not my primary driver. It’s mostly used for long and longer distances. It does get some around town use but recently I’ve been driving about 70 miles round trip (35 each way mostly freeway driving one way and clear freeway driving the way back) 4-5 days a week for the last couple of months. That will probably continue for the next several weeks. Before that, it wasn’t getting that much driving. Some around town and the occasional freeway trip of about 60 miles to get everything up to operating temperature.

I’ve used it over the years to trailer vehicles and sadly it’s only been off-road a few times and even then that was limited.
I'd say as long as you're following the interval "B" service schedule here at the (former) WJJeeps website, you in general should be good to go.


Stuff not listed like tie rod ends, control arm bushings, motor & trans mounts are on an "as needed" schedule IMO.
 

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DO NOT OVERHEAT THAT ENGINE!!

What I mean by that is baby it and maybe it will reach 200,000 Miles. And that's a big maybe.

I learned the hard way with my 1999.

That engine was a poor design by Chrysler Coporation and over time will drop the valve seats if it runs too hot.

And by running to hot I mean driving it fast like a regular car, etc.

That engine has weak internals that will not hold up over time unless you baby it.

Upgrade all the internals and you should be ok for several hundred thousand miles. Otherwise that engine will go south fast.

Hope this helps.
 

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04 WJ Overland
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Just keep up on maintenance, specifically the cooling system and you should be fine. I have a regular 4.7 in a Dakota around 174k and a HO in my WJ with 203k. IMO the 4.7 is a decent engine but its not a Honda. It does require you keep up on maintenance

If you haven't done so yet, I would:
  • Full visual inspection of the WJ. See if anything is worn or looking tired. Bushings, shocks, tie rod ends, bearings, random evap hoses near the tank etc. Inventory what could be replaced, should be replaced and must be replaced
  • Replace everything in your cooling system in one shot. Radiator, water pump, thermostat, thermostat housing (if its warped) and all hoses. Run a good quality coolant. If your 4.7 has the hydro fan, make sure it actually works. If its conventional, check that the fan clutch isn't dead and that your e-fan relay is still good. It sucks to discover that none of this works on the side of Highway 5 when its 110 out.
    • In my experience, most Dodge/Jeep factory cooling solutions have a life expectancy of 5 years or 60-75k. You can get another year or two out of it if you wait for something to start to leak, but then you run the risk of having a really bad day.
  • Check out the PCV system. If the lines are getting plugged or the PCV valves them selves are cruddy, your oil consumption will go up. Cleaning them out is fairly straight forward and the valve itself is cheap.
  • A transmission fluid + filter change would be a good idea.
  • A/C check or recharge if needed
 

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2002 jeep Grand Cherokee 4.7
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My 2002 WJ Laredo (4.7 V8, 4 WD, towing and up-country suspension packages) is coming up on 100,000 miles. That’s not a typo - that’s 100K.

I’ve been getting the oil changed about every 3,000 miles and whatever fixed when it’s needed. But I’m curious if there’s anything extra I should do when it hits 100,000.

It’s not my primary driver. It’s mostly used for long and longer distances. It does get some around town use but recently I’ve been driving about 70 miles round trip (35 each way mostly freeway driving one way and clear freeway driving the way back) 4-5 days a week for the last couple of months. That will probably continue for the next several weeks. Before that, it wasn’t getting that much driving. Some around town and the occasional freeway trip of about 60 miles to get everything up to operating temperature.

I’ve used it over the years to trailer vehicles and sadly it’s only been off-road a few times and even then that was limited.
you should use Shell Rotella 10w-30 or 10w-40 oil only and Peak orange hoat Organic Acid Technology antifreeze only....

serious about keeping your engine cool when you refill your antifreeze once it is full you must take out the vent plug it is a hex plug on top of the timing cover casting that is the return to the radiator by a large hose on the top drivers side of the radiator... take off the radiator cap...now run the engine at idle to get all air out of the engine passages and radiator you will see small bubbles coming out of the vent plug area it takes quite a while to get all air out of the engine this is the only way to vent all air out of the engine and might take as long as a hour just let it idle and watch for air bubbles at the vent plug. ive done mine some times ill just get an 1/2 hr and tighten up the vent hex plug and put the radiator cap back on. then the next day ill do it again for another 1/2 hr i might even do it for a few days until i see not one air bubble coming up at the vent plug....

as far as oil always use SHELL ROTELLA 10w-30 or 10w-40 check oil before you start it after a night of dripping oil back to the oil pan. . just check the level in the morning before you start it...not everyday but at least once a month always before you start it up...or before your going to take it on a long trip...

transmission fluid ATF+4 must be checked once engine is totally warmed up running in neutral on the transmission then is the time to pull the dip stick and check the level of fluid.

as far as your transfer case look on the stick next to the shifter and write back as to what different positions to can choose your transfer case. or get under the jeep on the back side of the transfer case will be a round metal label with Red color and some stamping on it. those stamped numbers will tell you what TC you have. just write back and you will receive feed back on what fluid you need to use...there are 242hd, 237..blah blah blah many of em...

then you have the differentials and they too have different axles and use different fluids according to which diffs you have. no big deal the DMV numbers will give you the build sheet of what options went into the build at the factory....there is a web site that you punch in the DMV numbers and it will tell you everything. sorry i cant remember the web site....
 

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2004 WJ Overland
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DO NOT OVERHEAT THAT ENGINE!!

What I mean by that is baby it and maybe it will reach 200,000 Miles. And that's a big maybe.

I learned the hard way with my 1999.

That engine was a poor design by Chrysler Coporation and over time will drop the valve seats if it runs too hot.

And by running to hot I mean driving it fast like a regular car, etc.

That engine has weak internals that will not hold up over time unless you baby it.

Upgrade all the internals and you should be ok for several hundred thousand miles. Otherwise that engine will go south fast.

Hope this helps.
Ummmmmm, yeah......

I'm at 242k and average 3500miles a month on mine. It definitely hasn't been babied and is still running strong.

I've had it in the 250° range going through the mountains, have driven on a blown head gasket & then put another 5k on it with BarsLeak head gasket sealer before I pulled the heads to get it properly fixed. No dropped seats either, by the way.

The whole "you've got to baby it and you'll be lucky to reach 200k" thing sounds pretty stupid.

And no, you don't need to "upgrade all the internals" on the engine.

Do the maintenance, first of all. Then understand the 4.7 doesn't need to be babied they way some people think.

Good grief.
 

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Mine went 30000 kms with low oil pressure at idle and I drove the snot out of it before it started to rod knock. Fairly impressive imo. Litterally was driving it full tilt and I swear I heard what sounded like a head gasket go? Idk lol. I changed the engine and tbh I'm a tad nicer to it now.
 

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I'm at 300,000 miles with just scheduled maintenance. Burns no oil between changes. Mobil 1 ever time. All it's ever needed outside of scheduled stuff is 2 water pumps that I changed before they totally failed thus no over heats.

Best thing you can do is idle for 30 seconds before you shut it off, this reduces the heat soak from the exhaust manifolds into the head and negates the vale seat drop issue with always happens after a hot shutdown.
 

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2002 Jeep WJ Grand Cherokee
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When you roll over 100k, here is what I would do. It is a long list but I am a nut. I kinda ordered this list in terms of what is easiest and/or more important.
  1. Air filter
  2. PCV
  3. Serpentine belt
    • Inspect all pulleys and accessories when belt is off: idler/tensioner, alternator, A/C compressor, P/S pump, harmonic balancer, water pump
  4. Fluids, fluids, fluids
    1. Engine oil & filter (of course)
    2. Front & rear differential fluids
    3. Transfer case fluid
    4. Transmission fluid and filters
      1. No flush. Instead, change fluid/filter, then drive a week. Change fluid again, drive a week. Change fluid again -- should be good.
    5. Coolant flush
    6. Brake fluid bleed
    7. Power steering bleed
  5. Radiator hoses and thermostat
  6. Water pump (inspect/replace)
  7. Spark plugs
  8. Brake pads and rotors
  9. Suspension
    1. Shock absorbers
    2. Grease ball joints, inspect, replace if needed
    3. Control arm bushings, inspect for wear ... frankly, knowing what I know now, I would replace all the rubber. After 20 years, the thing rides so much better when the rubber is fresh. But maybe not so bad with "only" 100k miles. Upper and lower, front and rear.
    4. Rear upper control arm ball joint ... if you are going to replace the rear UCA bushings, might as well do this.
    5. Sway bar end links
    6. Spring isolators
    7. Bump stops: inspect, replace if toasted
  10. Steering (inspect/replace)
    1. Tie rod ends
    2. Drag link ends
  11. Fuel filter
  12. Inspect for leaks
    • CVV system
    • Valve cover gaskets
    • Camshaft access port seals
    • Timing chain cover
    • Engine main seals
    • Engine oil pan
    • Pinion seals, front and rear
    • Transfer case output seals
    • Rear axle seals
    • Front CV joints
  13. Driveshaft ujoints (inspect/replace)

That's about all I can or want to think of at the moment. Beginning somewhere around item 9 (suspension), you could always just stick with the if-it-aint-broke-dont-fix-it philosophy.
 

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Perhaps I missed it, but I didn't see anyone mention replacing the heater core. At a shop it will cost you $1K+, as it is an 8-10 hour job. You can DIY it, but it's a chore. It seems that they all leak at some point, so just something to plan for. :( Lots of details in this thread, along with other things to fix while it's apart, to greatly increase airflow from the dash vents: How To - Get plenty of air from your dash vents! - JeepForum.com
 

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Great list @GmanWJ.... Pretty much identical to my run down of any new to me used car. Even if it already has fresh fluids in it, I trust no one and have my own preferred fluids. Out with the whatever was in there, in with the piece of mind.

Don't forget to clean the screen in the bottom of the PS reservoir. Also inspect steel fuel, trans, and brake lines as well as the rubber brake lines at the calipers (and at the rear axle). Brake lines especially like to blow when you need them the most! In the WJ, the brake line likes to rot before the rubber line at the rear axle, and the trans cooler lines like to rot behind the white plastic clips on the side of the trans.

As far as the heater core goes, I would definitely replace it if I had the dash out for another reason, but there is not a chance I am yanking that dash in the name of prevention. I'll wait until it leaks. My 5th WJ, and I've yet to have that misfortune. I consider myself incredibly lucky.
 

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I’ve been getting the oil changed about every 3,000 miles and whatever fixed when it’s needed. But I’m curious if there’s anything extra I should do when it hits 100,000.
IMO you should do the timing chain guides and chains, the water pump, a new motorad thermostat, and the valve cover gaskets.

This is the first engine that Chrysler used after Mercedes bought them, and they need exactly the same care and feeding as the 4.2l in a SEL420 does (it's almost the same engine), which is timing chain guides and chains, the water pump, a new motorad thermostat, and the valve cover gaskets.

As other users pointed out, you can't let this engine leak or get hot. Like, if you see three drips you need to fix it RIGHT NOW. Or a leaky heater core (which will keep the cooling system from building proper pressure). Merc stuff doesn't take neglect at all, which Jeep people either never got communicated, or lost the message in translation.
 
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The 4.7 was originally an AMC design, Benz added some touches to it but the basic architecture was conceived by American Motors. Another tidbit... The WJ was originally coded "SJ" for "Super Jeep".
 
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The 4.7 was originally an AMC design, Benz added some touches to it but the basic architecture was conceived by American Motors. Another tidbit... The WJ was originally coded "SJ" for "Super Jeep".
So, you might be right and I'd not heard that. Considering that Jeep had been buying drivetrains from GM for the Cherokee, that's really shocking to me that they independently developed an engine that is so similar to what Merc was selling in the 1980s.

In the decade I was in a tool truck I had a Merc specialist with three guys who had a combined 80 years of MB experience, all of them expat MB of Laguna Niguel or Fletcher Jones MB (the two biggest MB dealers in the US) service managers, and I've seen them do 100K service (timing chain guides, waterpump, valve cover gaskets) on literally hundreds of M126 engines in SEL420s, 560s, and a few other cars I forget about of that era.

The first time I saw a 4.7 apart at the Jeep dealer all I could think was "welp thats Merc and their sticky fingers taking over Chrysler engineering"

If you want to see one taken down for timing chains and guides, it's here: https://flic.kr/p/R7fNJc


I'm no historian. Point being if you treat a 4.7 like a M126 you will have a lot less problems, and the Jeep people missed the memo on that one.
 

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The 4.7 was originally an AMC design
Fact. It was the "new" 287ci v8 for AMC. Designs for the engine were nearing completion when Jeep (AMC) was purchased by Chrysler in 1987. Daimler (Mercedes) bought majority shares in Chrysler the following year. The 287 sat on ice at Chrysler and was finally born into production in 1999. Also derived from this design was the PowerTech 3.7 v6, which is near literally the 4.7 with 2 cylinders lopped off....

I even have an original AMC 287 sticker I snatched from eBay under the hood of my WJ as a nod to the engine's AMC roots.
Rectangle Line Font Gas Symbol
 
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Daimler (Mercedes) bought majority shares in Chrysler the following year. The 287 sat on ice at Chrysler and was finally born into production in 1999.
Merc bought Chrysler in 1998, not 1988.


There is some science fiction level "suspension of belief" to think that Merc buys Jeep and then revives a now 12 year old design - that looks strikingly similar to what Merc had been using since 1983 - but was so cutting edge that it became the corporate V8 in the Dodge truck line for till 2013 after they sandbagged it for a decade after buying AMC (who hadn't built a new engine design since the 50's, and had been building Jeeps with GM powertrain), but like I wrote earlier, I'm not a historian. If you say so.

Either way, doesn't matter. Change your timing chains and guides every 100K.
 

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